Uranium (U) is hazardous material can cause chemical and radiological toxicity, e.g., kidney toxicity and health effects associated with radiation. In Korea, where shallow weathered granitic aquifers are ubiquitous, several previous studies have reported high level of radioactivity in shallow groundwater. This eventually led to the closure of 60 out of 4,140 groundwater production wells in South Korea. Here, we examined aquifers currently dedicated for drinking water supply and investigated the 11,225 dataset of 103 environmental parameters. This dataset includes 80 physical parameters associated with the hydraulic system and 23 chemical parameters associated with waterrock interactions. Among hydraulic parameters, coarse loamy texture in subsoil displayed a notable relation with U concentration level, implied it is controlling the leaching of U from host rocks. Fluorine (F), is one of major products from water-rock interaction in granitic aquifer, exhibited high correlation with U concentration distribution. Positive relation of F concentration with uranium level suggested the dissolved U originated from groundwater interacted with granites. Conclusively, we found that infiltration capacity of soil layers and (2) aqueous speciation in groundwater formulated by interaction of groundwater with local solids, played important role for U concentration in granitic aquifer.

• YeoJin Ju(Korea Atomic Energy Research Institute (KAERI)) Corresponding author
• Vikram Thapar(Cornell University)
• Ji-hun Ryu(Korea Atomic Energy Research Institute (KAERI))